The FDA has granted full approval to rucaparib (Rubraca) for some adults with advanced prostate cancer that has spread and is no longer responding to hormone (testosterone‑lowering) treatment, when their cancer has a BRCA gene mutation and they have already been treated with at least one newer hormone‑blocking medicine (such as abiraterone or enzalutamide).
What the TRITON3 Study Showed
In the TRITON3 clinical trial, men with BRCA‑mutated metastatic castration‑resistant prostate cancer who took rucaparib went longer before their cancer worsened on scans compared with those who received the doctor’s choice of standard treatment (about 11.2 months vs 6.4 months on average). This improvement in delaying cancer growth was mainly seen in people whose tumors had BRCA mutations, rather than ATM mutations.
Earlier Accelerated Approval (TRITON2)
In 2020, rucaparib previously received an earlier, “accelerated” FDA approval for a similar group of patients who had also already received a taxane chemotherapy drug. That earlier decision was based on the TRITON2 study, where tumors shrank in about 44% of patients treated with rucaparib, and many of these responses lasted a long time.
How TRITON3 Was Designed
In TRITON3, men had metastatic castration‑resistant prostate cancer with BRCA1/2 or ATM alterations and had already received a newer hormone‑blocking therapy. They were randomly assigned to take rucaparib pills twice daily or to receive standard therapy (docetaxel chemotherapy or another newer hormone‑blocking drug), and researchers measured how long it took for cancer to grow again on imaging and how long patients lived overall.
Benefits Across Age Groups
Updated analyses showed that rucaparib helped men of different ages—including those under 65, 65 to 74, and 75 and older—go longer before their cancer progressed, compared with standard treatment in each age group.
Common Side Effects
The most common side effects of rucaparib include:
- Tiredness or low energy
- Low red blood cell counts (anemia), which can cause fatigue or shortness of breath
- Nausea
- Decreased appetite
- Diarrhea
Because of these risks, regular blood tests and promptly reporting new or worsening symptoms to the care team are important while taking this medicine.
References:
Bryce AH, Piulats JP, Ryan CJ, et al. Efficacy of rucaparib vs physician’s choice in patients with BRCA-mutated metastatic castration-resistant prostate cancer by age: Results from the TRITON3 study. Presented at: Society of Urologic Oncology Annual Meeting; December 2-5, 2025; Phoenix, Arizona. Poster #176.
Fizazi K, Piulats JM, Reaume MN, et al. Rucaparib or physician’s choice in metastatic prostate cancer. N Engl J Med. 2023;388(8):719-732. doi:10.1056/NEJMoa2214676
